1. Field of the Invention
The present invention generally relates to an ultrasonic imaging method and apparatus for supplying impedance matching fluid to a body being imaged, and more particularly, to such a method and apparatus wherein the impedance matching fluid is supplied to the body being imaged in a manner that improves the efficiency of the ultrasonic imaging procedure as well as patient comfort.
2. Background Discussion
Ultrasonic imaging is used to perform non-invasive of imaging of an object, such as the body of a biological organism. Its non-ionizing character, moderate requirements in terms of signal processing and computation support, compactness and image quality all favor the use of ultrasound whenever conditions permit. With the exception of body areas which are subject to uncontrolled multiple reflections, such as, for example, the skull and areas which fundamentally possess poor sonic transmission characteristic, such as the lungs, most areas of the body have been successfully made the subject of ultrasonic diagnosis or screening.
Known ultrasonic imaging systems include arrangements using a hand-held scan head coupled by a cable to a processing and display unit. The scan head typically includes an array of ultrasonic transducers that transmit an acoustic signal in the form of ultrasonic energy into the region being imaged and receive reflected ultrasonic energy returning from the region. The transducers convert the reflected ultrasonic energy into electrical signals which are transferred over the cable to the processing unit which applies appropriate beam forming techniques, such as dynamic focusing, to combine the signals to generate an image of the region.
In order to propagate the acoustic signal and to minimize echoes at the point where the acoustic signal enters the object being imaged, a fluid having an acoustic impedance which substantially matches that of the object is typically situated between the ultrasonic transducer head of the imaging device and the object being imaged. When performing ultrasonic medical imaging, the impedance matching fluid utilized typically has an acoustic impedance which substantially matches that of human body tissue. Such impedance matching fluids generally have the consistency of a gel.
For ultrasonic imaging systems using a held-held transducer head, the impedance matching fluid or gel is typically applied to the patient""s skin overlying the area of the body being imaged using a squeeze bottle dispenser that deposes a glob of the impedance matching gel on the skin of the patient. The hand-held transducer head is then placed in the glob of impedance matching fluid and used to spread the impedance matching as the transducer head is moved over the area being imaged. More gel must be applied after all the gel has been spread and/or as the gel dries out during the imaging procedure. Reapplication of the gel may be required as many as thirty times during a given ultrasonic imaging procedure.
As a result, frequent re-application of the impedance matching gel is required during the imaging procedure thereby reducing the efficiency of process and increasing the time that is required to complete the examination as well as patient discomfort. In addition, the gel in the squeeze bottle dispenser typically has a temperature at or near the ambient room temperature. The room temperature of the gel coupled with the evaporation of the gel on the skin makes the gel feel cold to the patient, thereby further increasing patient discomfort.
Accordingly, it is an object of the present invention provide a method and apparatus for applying an impedance matching fluid to the body of a patient having an ultrasonic imaging procedure in a manner that improves the efficiency of the ultrasonic imaging procedure as well as patient comfort.
Another object of the present invention is to solve the problem of constantly having to stop and re-apply the impedance matching gel to the patient during the ultrasound imaging procedure.
Still a further object of the present invention is to increase patient comfort by warming the gel that is applied.
An advantageous feature of the present invention is the ability to easily retro-fit the apparatus to existing ultrasound imaging devices.
Another advantageous feature of the apparatus of the present invention is that it can be used with ultrasonic scan heads having different shapes and configurations.
These and other objects, advantages and features of the present invention are achieved, according to one embodiment thereof, by an apparatus for heating and supplying an impedance matching fluid in gel form to the body of a patient having an ultrasonic imaging procedure, wherein the apparatus comprises: 1) a reservoir of containing the impedance matching gel; 2) a heater, inserted into the reservoir, for warming the gel, the heater having a thermostat for setting the temperature of the gel; 3) a pumping arrangement for supplying the heated gel, via a conduit, to the hand-held transducer head of the ultrasonic imaging device, the pumping arrangement having a vacuum activated on/off switch located for easy access at the transducer head; and 4) a low gel sensing system for providing an indication when the gel in the reservoir drops to a predetermined quantity to prevent overheating.
According to a further embodiment of the present invention, the low gel sensing system comprises a warning system including an arrangement for sensing the weight of the reservoir such that a series of switches: a) illuminate a green light when sufficient gel is in the reservoir to prevent overheating and b) active a red light and a piezoelectric alarm when the weight of the gel containing reservoir drops below a predetermined weight.
The present invention also includes a method of applying an impedance matching fluid to a patient having an ultrasonic imaging procedure which, according to one embodiment thereof comprises the steps of: heating the impedance matching fluid to a given temperature; and applying the heated impedance matching fluid to the patient.
According to a further embodiment of the present invention, there is provided a method of applying an impedance matching fluid to a patient having an ultrasonic imaging procedure using a hand-held ultrasonic transducer of an ultrasonic imaging device, the method comprising the steps of: heating impedance matching fluid contained in a reservoir to a given temperature; providing a supply of heated impedance matching fluid from the reservoir to the hand-held ultrasonic transducer; and applying the heated impedance matching fluid to the patient from the hand-held ultrasonic transducer. This method can further comprise the step of: generating a low impedance matching fluid indication when the impedance matching fluid in the reservoir drops to a predetermined quantity to advise the operator that more gel needs to be added to the reservoir and/or to prevent overheating of the impedance matching fluid by the heater due to the small quantity of gel in the reservoir.